The performance of an internal combustion engine may be adversely affected by the formation of deposits in or around the fuel injection system and combustion chamber. Even when present in minor amounts, these deposits can cause a noticeable reduction in the performance of the engine, an increase in fuel consumption, and the production of exhaust pollutants. It is generally accepted that deposit formation is largely dependent on the fuel composition, and to a lesser extent, on the engine design and on the operating conditions of the engine. In an effort to control deposit formation, considerable efforts have been directed toward developing fuel compositions that have a reduced tendency to cause the formation of deposits. In particular, the majority of the research has been directed toward developing fuel additives that either prevent or reduce the formation of such deposits.
For example, U.S. Pat. No. 5,912,189 discloses compositions that are useful as fuel additives for reducing intake valve deposits. Such compositions comprise the reaction product of: (a) a cyclic compound containing at least one nitrogen and at least one carbonyl group; (b) an aldehyde or ketone; and (c) an etheramine.
U.S. Pat. No. 5,873,917 discloses compositions that are useful in reducing intake valve deposits. Such compositions contain: (a) a polyether alcohol; (b) a hydrocarbylphenol; and (c) optionally, a nitrogen-containing dispersant.
U.S. Pat. No. 5,514,190 discloses fuel additive compositions for controlling intake valve deposits. These compositions comprise: (a) a gasoline-soluble Mannich reaction product of a high molecular weight alkyl-substituted phenol, an amine, and an aldehyde; (b) a gasoline-soluble poly(oxyalkylene) carbamate; and (c) a gasoline-soluble poly(oxyalkylene) alcohol, glycol, or polyol, or mono or diether thereof.
U.S. Pat. No. 5,697,988 discloses a fuel additive composition that reduces engine deposits and controls octane requirement increases in engines. The fuel additive composition comprises: (a) a Mannich reaction product of a high molecular weight alkyl-substituted phenol, an amine, and an aldehyde; (b) a polyoxyalkylene compound; and (c) optionally, a poly-.varies.-olefin.
Despite such efforts, further improvements in the art are needed. Specifically, what are needed are fuel additives that function as fuel detergent promoters that prevent or reduce deposit formation in engines, fuel compositions containing such fuel additives, and a method for controlling the formation of deposits in engines.